This method, in which you hugely cut down how much you eat, is popular because it’s seen as a quick fix, but sadly there's no such thing. Crash diets might help you to lose a few pounds at first, but they won't help you to stay a healthy weight in the long run. Usually as soon as you stop restricting your calorie intake, you will put the weight straight back on again.
This happens because if you lose weight too quickly, you tend to lose a lot of lean body tissue – muscle – as well as fat. When this happens, your body starts to work more slowly, meaning that it needs fewer calories to function day-to-day. That's why the weight piles back on so quickly once you go back to your usual eating habits. Your body has adjusted to a lower calorie intake, so the extra calories are stored as fat.
If you’re overweight and want to lose some, the trick is to set realistic goals. Aim to lose weight at a rate of about 0.5kg (1lb) per week.
The ‘cabbage soup diet’, the ‘maple syrup diet’, the ‘blood group diet’ – no sooner does one fad diet lose popularity than another one comes along, promising to help you lose weight through one method or another. A healthy, balanced diet is essential for good health and if you cut out entire food groups, as advertised in some diets, it can be dangerous. No single food contains all the nutrients and fibre you need to stay healthy, so it's important to eat a range of foods from the five main food groups.
If you’re trying to lose weight, rather than cut something out completely, try to eat less fat and sugar and replace them with more of other food groups, such as fruit and vegetables. Weight for weight, fat has more than twice the calories of carbohydrates and protein. So remember to satisfy your hunger with bread, potatoes, rice and pasta when trying to lose excess weight.
Try to find low-fat alternatives to creamy sauces and buttery toppings, and choose cooking methods that keep the overall fat content low. And don't forget that a large portion of healthy pasta still stacks up a lot of calories. If you serve food on smaller plates, it can help you to eat sensible portion sizes.
Also watch out for ‘reduced-fat’ foods. These may not be low in fat at all – a ‘reduced-fat’ product must just have a third less fat than the standard product, so it may still be high in fat (‘75 percent fat-free’ still means the food is a quarter fat). Alternatively, the product may contain lots of salt and sugar.
Although diets such as the Atkins diet advocate cutting out fruit and vegetables, it’s important to aim to include at least five portions of these in your daily diet. Not only are fruit and vegetables rich in essential vitamins, minerals and fibre, but steamed, boiled or raw, they are both filling and low in calories.
Most people find it easier to lose weight by using a two-pronged approach that combines a lower-calorie diet with exercise. However, some activity is less useful than others. Exercising until it hurts and you ‘feel the burn’ sits firmly in the less useful category, especially if you’re starting to be active for the first time, or are returning to exercise after a period of inactivity. A relatively unfit person running hard for 10 minutes a couple of times a week is unlikely to shift much weight – and in fact, it could even be dangerous.
According to the UK Department of Health, to stay healthy you need to do at least 30 minutes of moderate exercise, such as brisk walking or swimming, on five or more days a week. You can break this up into several shorter chunks of 10 to 15 minutes throughout the day if that's easier for you.
If you’re overweight or obese, you will probably need to do more than this. Moderate activity should increase how fast your heart beats and make you feel slightly warm and a little out of breath. If you're not sure if you're doing enough or the right sort of physical activity, talk to your GP.
You don't become overweight by eating the occasional chocolate bar or cream cake if you have an otherwise healthy, balanced diet. Both putting on weight and slimming down to a healthy weight (and then maintaining it) really come down to lifestyle habits. Successfully losing weight is more about shifting these patterns than poring over the precise calorie content of every food you eat.
Make sure that you eat a healthy, balanced diet and build some activity into your daily life, such as walking the kids to school instead of driving or taking the stairs instead of the lift. It should be a simple way to help you reach a healthy weight and, more importantly, to stay there.
If you find it difficult to go it alone, remember that support is available. You could join a reputable slimming club, for example. It’s also important to take steps to reduce your weight and at a pace that works for you.
If you try to change all your habits overnight it may be too much. Focus on a few small changes at a time as this may be more effective for you in the long term. As well as getting the right support, it’s a good idea to monitor yourself. For example, enter everything you eat in a food diary so you can reflect on your diet – it may help you to lose weight and keep it off.
Produced by Rachael Mayfield-Blake, Bupa Heath Information Team, November 2012.